About 2500 children attending grades 1 through 12 at three schools in Robeson County, North Carolina, are exposed to 1) fluoridation of the school water supply at four and one-half times the level estimated to be optimum for community fluoridation in the same geographic areas, 2) weekly mouthrinsing with 0.2% NaF solution. Teachers dispense 10 millimeters of solution to each participant-child and supervise the one-minute rinsing procedure which is carried out in the classroom. To evaluate the long-term benefits of the combined treatments on the prevalence of dental caries, pre-treatment clinical data will be compared with the data obtained every two years until the completion of the program in 1984. Base line examinations using the DMF tooth and surface index were conducted in September 1972. Follow-up examinations were made in November/December, 1974. The project is currently in its third year.